Effects of gastrointestinal motility on obesity

Background: Changes of gastrointestinal motility, which are important related to the food digestion and absorption in the gastrointestinal tract, may be one of the factors in obesity-formation. Aims: The changes of gastrointestinal motility were explored in the rats from diet-induced obesity (DIO), diet-induced obese resistant (DR) or control (CON) by diet intervention. Methods: After fed with a high fat diet (HFD), 100 male Sprague-Dawley rats were divided into DIO, DR and CON groups. The rats from DIO and DR groups were fed with HFD, and CON with a basic diet (BD) for 6 weeks. Body weight, energy intake, gastric emptying, intestinal transit, motility of isolated small intestine segments and colon's function were measured in this study. Expression of interstitial cells of Cajal (ICCs) and enteric nervous system (ENS) - choline acetyltransferase (ChAT), vasoactive intestinal peptides (VIP), substance P (SP) and NADPH-d histochemistry of nitric oxide synthase (NOS) were determined by immunohistochemistry. Results: Body weight and intake energy in the DIO group were higher than those in the DR group (p < 0.05). Gastric emptying of DIO group rats (78.33 +/- 4.95%) was significantly faster than that of DR group (51.79 +/- 10.72%) (p < 0.01). The peak value of motility in rat's duodenum from the DR group was significantly higher than that in the DIO group (p < 0.05). In addition, the expression of interstitial cells of Cajal (ICC), choline acetyltransferase (ChAT), substance P (SP), vasoactive intestinal peptides (VIP) and neuronal nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) in the intestine of rats were significantly increased in the DIO group when compared to the DR group (p < 0.05). Conclusion: A faster gastric emptying, a weaker contraction of duodenum movement, and a stronger contraction and relaxation of ileum movement were found in the rats from the DIO group. It indicated that there has effect of gastrointestinal motility on obesity induced by HFD.